Dental handpieces which incorporate pneumatic or electric turbines for selectively rotating cutting and polishing tools have been in use for many years. For example, such handpieces are disclosed in U.S. Pat. Nos. 3,946,490; 4,983,121; 4,941,828; and 4,921,424. However, in recent years concern has arisen over the possible transmission of disease through the use of non-sterile handpieces. Whereas wiping a handpiece with a disinfectant was once considered sufficient to obviate disease transmission, it is now considered an inadequate procedure, and autoclaving or chemiclaving of handpieces between patients is now recommended. However, repeated autoclaving or chemiclaving tends to damage the turbines of conventional handpieces and shorten their useful life. In this regard, modern sterilization techniques can cause rusting metal components, changes in metal tolerances, bearing cage fractures, lubricant degradation, and gasket and o-ring degradation.
Efforts have been made to design handpieces turbines which better withstand sterilization. For example, in some cases the turbines of the handpiece have been provided with ceramic ball bearings to increase bearing life and obviate the need for the use of a lubricant. Further, in some cases heat resistant O-rings are being used. For example, the 430 SWL handpiece manufactured by Star Dental, a division of Den-Tal-Ez, Inc. of Lancaster, Penna., incorporates such features. However, such features offer only a partial solution to the problem.
Therefore, it is an object of the present invention to provide a turbine for a dental handpiece which can withstand repeated autoclaving or chemiclaving.
It is another object of the present invention to provide a dental handpiece which does not require the use of ball bearings or lubricants.
Yet another object of the present invention is to-provide a dental handpiece which is lightweight, yet durable.
Still another object of the present invention is to provide a dental handpiece which is inexpensive to manufacture and maintain.